Method for querying and for subscribing pcf binding events for an address range in a 5g system

ABSTRACT

A method for subscribing for Policy Control Function (PCF) binding events for an address range in a 5G system (5GS) includes: subscribing, from the NF Service Consumer to the functional entity, to binding information changes for one or a combination of subscriber parameters; sending, from the functional entity to the NF Service Consumer, a confirmation of the subscription; detecting, by the functional entity, a change of the stored binding information matching one or a combination of the subscriber parameters for one or more subscriber IDs; notifying of the change of the stored binding information, from the functional entity to the subscribed NF Service Consumer, by sending new PDU session binding information associated with the one or more subscriber IDs; and receiving, at the NF Service Consumer, the new PDU session binding information associated with the one or more subscriber IDs.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This is a division of U.S. patent application Ser. No. 17/228,732, filedApr. 13, 2021, which claims priority to European Patent Application No.EP 20169334.8, filed on Apr. 14, 2020, the entire disclosures of both ofwhich applications are hereby incorporated by reference herein.

FIELD

The invention relates to a method for enabling addressing andnotification of Protocol Data Unit (PDU) sessions and related NetworkFunctions (NFs) via an address range in a 5G system. In particular, theinvention relates to a method for querying and a method for subscribingto Policy Control Function (PCF) bindings events for an address range ina 5G system. The invention also relates to a method for querying and amethod for subscribing to information for a Media Access Control (MAC)or Internet Protocol (IP) address range, a Data Network Name (DNN),Subscription Permanent Identifier (SUPI), Generic Public SubscriptionIdentifier (GPSI), and/or a Single Network Slice Selection Identifier(S-NSSAI) in a communications system.

BACKGROUND

One of the promises of the 5G core (5GC) is to enable easy interactionwith external entity systems, i.e. third party systems, via exposedApplication Program Interfaces (APIs).

The 5GC is comprised by Network Functions (NFs), each of which being afunctional entity tasked with a defined set of responsibilities, asdefined in 3GPP TS 23.501.

FIG. 1 illustrates part of the 5G system architecture as standardized by3GPP. In particular, FIG. 1 illustrates some of the Network Functions(NFs) of a 5G Core as defined in TS 23.501 as well as a User Equipment(UE), e.g. a mobile phone or other device, connected to a Radio AccessNetwork (RAN), where the RAN is connected to the User Plane Function(UPF) (part of the 5GC), which allows the UE to have connectivity to aData Network (DN), e.g. an external data network, such as the Internet.

The 5GC is comprised on Network Functions (NFs), i.e. functionalentities, each functional entity tasked with a defined set ofresponsibilities, as defined in TS 23.501. Some of these functionalentities are shown in FIG. 1 such as: the Network Repository Function(NRF), Network Exposure Function (NEF), Policy Control Function (PCF),Unified Data Management (UDM), Binding Support Function (BSF), NetworkData Analytics Function (NWDAF), Access and Mobility Management Function(AMF), Session Management Function (SMF), User Plane Function (UPF).

The Network Exposure function (NEF) is tasked, as defined in TS 23.501,5.20 with supporting external exposure of capabilities of networkfunctions. External exposure can be categorized as monitoringcapability, provisioning capability, policy/charging capability andanalytics reporting capability

As per TS23.503, the Binding Support Function (BSF) is defined asfollows. The BSF stores information about the user identity, the DataNetwork Name (DNN), the User Equipment (UE) (IP or Ethernet)address(es), the Data Network (DN) information (e.g. Single-NetworkSlice Selection Identifier, S-NSSAI) and the selected Policy ControlFunction (PCF) address as well as the associated PCF instance ID and PCFset ID if available (clause 6.3.1.0 of TS 23.501) for a certain ProtocolData Unit (PDU) Session. This information is stored internally in theBSF.

The PCF registers, updates and removes the binding information from theBSF using the Nbsf management service operations API exposed by the BSF(TS 23.502). The PCF ensures that it is updated each time an IP addressis allocated or de-allocated to the PDU Session or, for Ethernet PDUSessions supporting binding of an Application Function (AF) requestbased on a MAC address, each time it has been detected that a MACaddress is used or no more used by the UE in the PDU Session.

Based on an operator's policies and configurations, the PCF determineswhether the same PCF shall be selected for the SM Policy associations tothe same UE ID, S-NSSAI and DNN combination in the non-roaming orhome-routed scenario.

As specified in TS 23.502, the NF(s) responsible for a given PDU sessionis established during the PDU session establishment procedure. Theprocedure is slightly different for the IP and Ethernet PDU sessiontypes.

FIG. 2 illustrates the PDU session establishment procedure of an IP PDUsession type and FIG. 3 illustrates the PDU session establishmentprocedure of an Ethernet PDU session type, as defined in TS 23.502.

In FIG. 2 , the SMF establishes a PDU session of IP type, in step S1A,and notifies, in step S2A, the PCF of the IP address (in IPv6 may bemultiple addresses) assigned to the PDU session regardless of whetherthe IP address was allocated by the SMF, an external AAA-S or any othermethod. In step S3A, the PCF registers the PDU session ID and associateddata in the BSF as the PCF responsible for a given PDU session (namedPCF Binding information). Finally, in step S4A, the SMF registers thePDU session ID in the Unified Data Management (UDM) as the SMFresponsible for this PDU session.

In FIG. 3 , the SMF establishes a PDU session of Ethernet type, in stepS1B, and registers, in step S2B, the PDU session ID in the UDM as theSMF responsible for this PDU session. MAC addresses are not assigned bythe 5GS. Instead, similarly to how an Ethernet switch operates, the 5GSystem learns the MAC addresses associated to a certain PDU session(analogous to a physical Ethernet port) by observing the source MACaddress of incoming Ethernet frames (TS 23.501). In step S3B, the UPFnotifies the SMF of any observed changes (e.g. MAC addressaddition/removal). In step 4B, the SMF notifies the PCF of the MACaddress(es) associated with the PDU session and, finally, in step S5B,the PCF updates the PCF Binding information in the BSF with the MACaddress(es).

TS 29.521 defines the information stored in the PCF Binding informationin the BSF by the PCF. The parameters are listed in table 1 below:

TABLE 1 Excerpt of PcfBinding parameters (M: Mandatory, O: Optional, C:Conditional) Attribute P Cardinality Description SUPI O 0 . . . 1Subscription Permanent Identifier GPSI O 0 . . . 1 Generic PublicSubscription Identifier IPv4 address C 0 . . . 1 The IPv4 Address of theserved UE. IP domain O 0 . . . 1 IPv4 address domain identifier. IPv6prefixes C 0 . . . 1 The IPv6 Address Prefix of the served UE.Additional IPv6 prefixes O 1 . . . N Additional IPv6 Address Prefixes ofthe served MAC address C 0 . . . 1 The MAC Address of the served UE.Additional MAC O 1 . . . N Additional MAC Addresses of the served UE.DNN M 1 DNN S-NSSAI M 1 The identification of slice. PCF instance ID O 0. . . 1 PCF instance identifier

The BSF Application Programming Interface (API) provides a methodallowing to retrieve the Session binding information, i.e. PCF addressinformation of a given tuple. An excerpt of the allowed Query parametersis shown in table 2 below.

TABLE 2 Excerpt of query parameters supported by BSF to query a singlePcfBinding resource (M: Mandatory, O: Optional, C: Conditional) Name PCardinality Description IPv4 C 0 . . . 1 The IPv4 Address of the servedUE. address IPv6 prefix C 0 . . . 1 The IPv6 Address of the served UE.The NF service consumer shall append ‘/128’ to the IPv6 address in theattribute value. MAC C 0 . . . 1 The MAC Address of the served UE.Address DNN O 0 . . . 1 DNN SUPI O 0 . . . 1 Subscription PermanentIdentifier GPSI O 0 . . . 1 Generic Public Subscription IdentifierS-NSSAI O 0 . . . 1 The identification of slice. IP domain O 0 . . . 1The IPv4 address domain identifier.

As per TS 29.503, the SMF registration can be queried if the UE ID isknown. The data is accessed by an Uniform Resource Identifier (URI)following the following scheme: /{UEID}/registrations/smf-registrations. The UE ID represents theSubscription Identifier SUPI or GPSI (TS 23.501 clause 5.9.2), e.g.IMSI, NAI, MSIDSDN. S-NSSAI and DNN may be additionally used.

The registration data the SMF registers for each PDU session containsthe following data, as shown in table 3 below, that is theSmfRegistration data (excerpt):

TABLE 3 Excerpt of SmfRegistration data Attribute name P CardinalityDescription SMF Instance ID M 1 NF Instance Id of the SMF PDU Session IDM 1 PDU Session ID S-NSSAI M 1 A single Network Slice SelectionAssistance Information DNN C 0 . . . 1 Data Network Name; shall bepresent if emergencyServices is false or absent PLMN ID M 1 Serving nodePLMN identity.

Given a single IP address (the same applies to a single MAC address), aconsumer can interact (e.g. request data, subscribe to events) with SMFand PCF responsible with that given IP address, i.e. the NFs that canreport on session-related information and policy-related information.

By using the information stored in the BSF (IP address→subscriber ID,PCF instance ID), UDM (subscriber ID→SMF instance ID), a consumer canfind out the NFs responsible for this UE.

FIG. 4 illustrates an exemplary interaction with the SMF and PCF given aknown IP address.

In FIG. 4 , step S11, an NF Service Consumer queries for PCF Bindinginformation for a given IP address to the BSF. In step S12, the BSFreplies with PCF Binding information including UE ID and PCF instanceID. In step S13, the NF Service Consumer queries PDU Session SMFregistration for the given UE ID to the UDM, and the UDM replies, instep S14, with SmfRegistration data including PDU session ID and SMFinstance ID. At this stage, in step S15, for a given IP address, the SMFand PCF are known to the consumer from the BSF and UDM registration. Instep S16, the consumer can then interact with the SMF and PCF (forexample, perform requests, subscribe to events, etc.) for the given PDUsession.

In more detail, 3GPP TS 29.503 defines that the SmfRegistrationinformation returned by the UDM has an array of SmfRegistration objects.In 3GPP TS 29.521, the PcfBinding information returned by the BSFcontains a single PcfBinding object (i.e. not an array). As such, aquery to the BSF can only return at maximum a single PcfBinding, i.e.only a single address can be resolved per query.

In some specific and realistic use cases, it can be assumed that anexternal entity system (such as, for example, a third party system) isnot aware of 5G System (5GS) identifiers and, instead, relies solely onIP addresses/MAC addresses to identify users such as, for example, theuse of secondary authentication and/or analytics.

With regard to the above mentioned first use case, the 5GS allowssecondary authentication to be used. An expected use case of secondaryauthentication are the 5G private networks provided by an operator.There, an external entity (e.g. Company X) can contract from a MobileNetwork Operator (MNO) a network for its private use.

Such a network may contain cells reserved for exclusive use for thisexternal entity's subscribers, deploy different functionality for use ofsuch subscribers (for example, 5G slices, local routing of some datatraffic, etc.) and also give authentication control to the third partyby using an Authorization and Accounting Server (AAA-S) under the thirdparty's control for secondary authentication.

The IP address allocated to each UE can, in this case, be managed by theAAA-S. The AAA-S authenticates subscribers and assigns IP addressesbased on external entity credentials that are independent of thecredentials used by the 5GS.

An example of this two-level authentication is a 5GS subscriberauthenticating towards the 5GS with its 3GPP credentials (IMSI stored inthe SIM) and the 5GS notifying that secondary authentication is required(for example, if there is an agreement with Company X such that CompanyX authenticates its subscribers itself). The secondary authentication isthen based on separate credentials (for example, the subscriberidentifies itself as a user@company-x.com).

FIG. 5 illustrates an exemplary two-level authentication in a 5Gcommunications system. The system comprises a User Equipment (UE) 1, a5GS 2, a Data Network (DN) 3 (e.g. the Internet), and an external entityAAA server 4 (AAA-S). In FIG. 5 , the key symbols symbolize credentials.The UE 1 has 3GPP credentials to access the 5GS (e.g. SIM card), wheresuch access is denoted with a solid line. In addition, the UE 1 also hasadditional credentials for authentication towards the external entityAAA server. The 5GS performs not only authentication based on the 5GScredentials, but also forwards authentication messages between the UEand the external AAA server. This indirect interaction between UE andexternal AAA server via the 5GS is denoted with a dotted line. In thisconfiguration, the 5GS authenticates based on the 3GPP credentials,whereas the external entity AAA server authenticates based oncredentials different than 5GS. In addition, IP allocation may be alsoperformed by the AAA-S.

The 5GS forwards authentication messages between the UE and the externalentity AAA-S and the AAA-S performs the authentication based on thecredentials provided by the subscriber.

From the perspective of the entity operating the AAA-S, users areidentified by its credentials and their assigned IP address. In case ofEthernet traffic, as specified in TS23.501, the MAC addresses are givenby the subscriber (the device's MAC address or the MAC addressesattached to the device), and the AAA-S can also specify a list of sourceMAC addresses that are allowed for a given PDU session. As such, MACaddresses are also linked to an authorized credential.

Therefore, in view of the above, the case arises where the externalentity managing the address space of 5GS subscribers does not use 5GSidentifiers (IMSI, GPSI).

With regard to the above mentioned second use case, the 5GS allows theuse of analytics. The Network Data Analytics Function (NWDAF) NF istasked with (as defined in TS 23.501): support data collection from NFsand AFs; support data collection from Operations, Administration andMaintenance (OAM); NWDAF service registration and metadata exposure toNFs/AFs; support analytics information provisioning to NFs, AFs.

SUMMARY

In an exemplary embodiment, the present invention provides a method forsubscribing for Policy Control Function (PCF) binding events for anaddress range in a 5G system (5GS), wherein the 5GS comprises a NetworkFunction (NF) Service Consumer and a functional entity, wherein thefunctional entity comprises binding information stored therein and thebinding information comprises: Protocol Data Unit (PDU) sessionsinformation and a list comprising one or more subscribers identities(IDs) and/or PCF instance IDs, the method comprising: subscribing, fromthe NF Service Consumer to the functional entity, to binding informationchanges for one or a combination of subscriber parameters, wherein thesubscriber parameters comprise: a MAC or IP address range, a DataNetwork Name (DNN), a Subscription Permanent Identifier (SUPI), aGeneric Public Subscription Identifier (GPSI), a Single Network SliceSelection Identifier (S-NSSAI), and/or an IP domain; sending, from thefunctional entity to the NF Service Consumer, a confirmation of thesubscription; detecting, by the functional entity, a change of thestored binding information matching one or a combination of thesubscriber parameters for one or more of the subscriber IDs; notifyingof the change of the stored binding information, from the functionalentity to the subscribed NF Service Consumer, by sending new PDU sessionbinding information associated with the one or more subscriber IDs; andreceiving, at the NF Service Consumer, the new PDU session bindinginformation associated with the one or more subscriber IDs.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described in even greaterdetail below based on the exemplary figures. The present invention isnot limited to the exemplary embodiments. All features described and/orillustrated herein can be used alone or combined in differentcombinations in embodiments of the present invention. The features andadvantages of various embodiments of the present invention will becomeapparent by reading the following detailed description with reference tothe attached drawings which illustrate the following:

FIG. 1 illustrates Network Functions (NFs) of a 5GC as defined in TS23.501;

FIG. 2 illustrates a flow for a PDU session establishment procedure ofIP type as defined in TS 23.502;

FIG. 3 illustrates a flow for a PDU session establishment procedure ofEthernet type as defined in TS 23.502;

FIG. 4 illustrates a flow of an exemplary interaction with the SMF andPCF given a known IP address;

FIG. 5 illustrates an exemplary two-level authentication in a 5GS;

FIG. 6 illustrates a flow of a BSF query for an address range accordingto an embodiment of the invention;

FIG. 7 illustrates a flow of a BSF subscription for a binding change inaddress range according to an embodiment of the invention;

FIG. 8 illustrates a flow for addressing NFs based on a subscriberaddress range according to an embodiment of the invention;

FIG. 9 illustrates a flow for notification of changes based on asubscriber address range according to an embodiment of the invention;

FIG. 10 illustrates a flow for application of information retrievalaccording to an embodiment of the invention; and

FIG. 11 illustrates a flow for application of event notificationaccording to an embodiment of the invention.

DETAILED DESCRIPTION

Conventionally, given an IP address range or MAC address range, there isno way to obtain from the 5G system a list of subscribers and no way toquery which Network Functions (NFs) are responsible for thesesubscribers. Instead, it is only possible to query individual addresses.

As an example, given an IP address range 10.0.0.0/16, querying everyindividual address would require 65,536 queries. Subscribing toevents/changes for found users would also require a subscription foreach individual subscriber. In this case, an external entity wouldinteract with the 5G system via the Network Exposure Function (NEF). TheNEF is tasked, as defined in TS 23.501, 5.20 with supporting externalexposure of capabilities of network functions. External exposure can becategorized as monitoring capability, provisioning capability,policy/charging capability and analytics reporting capability.

However, given the above status limitations, use of an IP range or MACaddress range to trigger action within the 5G system is not realizableand very inefficient.

Thus, it is conventionally not possible to map an IP range or MACaddress range to a group of subscribers (Subscription PermanentIdentifier (SUPI) or Generic Public Subscription Identifier (GPSI)).

Further, with regard to analytics, in order to monitor events (forexample, policy-related events from a PCF or session-related events froman SMF) for a given IP pool, MAC address range, DNN or slice,conventionally it is necessary for the Binding Support Function (BSF) tolocate the PDU session that needs to be monitored. Afterwards, it isconventionally necessary to subscribe at the correct NF responsible forthe given PDU session(s).

However, this is conventionally not possible without a brute-force scanof an address range (IP/MAC address range case) or conventionally notpossible at all for the other cases.

Conventionally, the following use cases cannot or can only verydifficultly be fulfilled.

For example, if a NF Service consumer possesses only an IP range, e.g.10.0.0.0/16 (e.g. IP range managed by the AAA-S, range to monitor),optionally a given DNN or slice ID (S-NSSAI) and requires to:

-   -   1) Query the NFs responsible for PDU sessions (e.g. SMF, PCF)        for information. This would require for a /16 IPv4 address range        more than 65,000 requests to the BSF. Exponentially increasing        the bigger the CIDR range.    -   2) Query the BSF for bindings if there is more than one expected        result.    -   3) Query the BSF for a full S-NSSAI or DNN (equivalent to        0.0.0.0 IP, i.e. “any IP”) unless the whole IP range in queried        (232 in the case of IPv4).    -   4) Keep updated on all events (e.g. SMF and PCF) regarding a        given address range (e.g. PDU session establishment, PDU session        release, added/removed MAC address for a given PDU session).        This would require frequent re-query of 1) and re-evaluation of        the returned results. There is current solution to subscribe on        the BSF to events (e.g. new binding, binding removed) for a        given address range, DNN or S-NSSAI.

In view of the above, exemplary embodiments of the present inventionprovide a method that provides functionality so that a 5G system can:given an address range (IP or MAC address), obtain the subscribers withaddresses within that range; subscribe to changes/events within theseranges (for example, what Policy Control Functions (PCFs) areresponsible for the subscribers in a given range; and enable addressingand notification of PDU sessions and related NFs via an address range ina 5GS.

According to a first aspect, the invention provides a method forquerying Policy Control Function (PCF) binding information for anaddress range in a 5G system (5GS), wherein the 5GS comprises a NetworkFunction (NF) Service Consumer, and a functional entity, wherein thefunctional entity comprises binding information stored therein and thebinding information comprises: Protocol Data Unit (PDU) sessionsinformation and a list comprising one or more subscribers identities(IDs) and/or PCF instance IDs, the method comprising the steps of:querying, from the NF Service Consumer to the functional entity, basedon one or a combination of query parameters, for all binding informationmatching the query parameters; and notifying, from the functional entityto the NF Service Consumer, any binding information that matches thequery parameters, wherein the query parameters comprise: a MAC or IPaddress range, a Data Network Name (DNN), Subscription PermanentIdentifier (SUPI), Generic Public Subscription Identifier (GPSI), aSingle Network Slice Selection Identifier (S-NSSAI), and/or IP domain.

According to a further aspect, the 5GS further comprises a Unified datamanagement (UDM), a Session Management Function (SMF), and a PolicyControl Function (PCF), the method further comprising the steps of:receiving, at the NF Service Consumer, the binding information, matchingthe query parameters, comprising list of subscriber IDs; querying, fromthe NF Service Consumer to the UDM, for SMF registration data based onthe list of subscriber IDs, replying, from the UDM to the NF ServiceConsumer, to the above query, with SMF registration data matching thelist of subscriber IDs, wherein the SMF registration data comprises oneor more PDU session IDs and/or SMF instance IDs; receiving, at the NFService Consumer, the SMF registration data; and interacting, from theNF Service Consumer with the SMF and/or the PCF, using the one or morePDU session IDs and/or SMF instance IDs.

According to a second aspect, the invention provides a method forquerying information for a MAC or IP address range, a Data Network Name(DNN), a Subscription Permanent Identifier (SUPI), a Generic PublicSubscription Identifier (GPSI), a Single Network Slice SelectionIdentifier (S-NSSAI), and/or IP domain, in a communication system,wherein the system comprises: an external entity, and a 5G system (5GS),comprising a Network Function (NF) Service Consumer, the methodcomprising the steps of: querying, from the external entity to the NFService Consumer, for information matching one or more of a combinationof query parameters, wherein the query parameters comprise: MAC or IPaddress range, DNN, SUPI, GPSI, S-NSSAI and/or IP domain; performing, atthe NF Service Consumer and the 5GS, a method according to any of theabove aspects; and notifying, from the NF Service Consumer to theexternal entity, of the information matching the query parameters.

According to a third aspect, the invention provides a method forsubscribing for Policy Control Function (PCF) binding events for anaddress range in a 5G system (5GS), wherein the 5GS, comprises a NetworkFunction (NF) Service Consumer, a functional entity, wherein thefunctional entity comprises binding information stored therein and thebinding information comprises: Protocol Data Unit (PDU) sessionsinformation and a list comprising one or more subscribers identities(IDs) and/or PCF instance IDs, the method comprising the steps of:subscribing, from the NF Service Consumer to the functional entity, tobinding information changes for one or a combination of subscriberparameters, wherein the subscriber parameters comprise: a MAC or IPaddress range, a Data Network Name (DNN), a Subscription PermanentIdentifier (SUPI), a Generic Public Subscription Identifier (GPSI), aSingle Network Slice Selection Identifier (S-NSSAI), and/or IP domain;sending, from the functional entity to the NF Service Consumer, aconfirmation of the subscription of the previous step; detecting, by thefunctional entity, a change of the stored binding information matchingone or a combination of the subscriber parameters for one or more of thesubscriber IDs; notifying of the change of the stored bindinginformation, from the functional entity to the subscribed NF ServiceConsumer, by sending new PDU session binding information associated withthe one or more subscriber IDs; and receiving, at the NF ServiceConsumer, the new PDU session binding information associated with theone or more subscriber IDs.

According to a further aspect, the 5GS further comprises a Unified datamanagement (UDM), a Session Management Function (SMF), and a PolicyControl Function (PCF), the method further comprises the steps of:querying, from the NF Service Consumer to the UDM, for SMF registrationdata based on the one or more subscriber IDs associated with the new PDUsession binding information; replying, from the UDM to the NF ServiceConsumer, to the above query, with SMF registration data matching theone or more subscriber IDs, wherein the SMF registration data comprisesone or more PDU session IDs and/or SMF instance IDs; updating, at the NFService Consumer, the SMF registration data; and interacting, from theNF Service Consumer to the SMF and/or the PCF, using the one or more PDUsession IDs and/or SMF instance IDs.

According to a fourth aspect, the invention provides a method forsubscribing to events for a MAC or IP address range, a Data Network Name(DNN), Subscription Permanent Identifier (SUPI), Generic PublicSubscription Identifier (GPSI), a Single Network Slice SelectionIdentifier (S-NSSAI), and/or IP domain, in a communications system,wherein the system comprises: an external entity, and a 5G system (5GS),comprising a Network Function (NF) Service Consumer, the methodcomprising the steps of: subscribing, from the external entity to the NFService Consumer, to event changes for information matching one or acombination of subscriber parameters, wherein the query parameterscomprise: the MAC or IP address range, DNN, SUPI, GPSI, S-NSSAI, and/orIP domain; performing, at the NF Service Consumer and the 5GS, themethod according to the second or previous aspect; notifying, from the5G system to the NF Service Consumer, of any event changes for the oneor combination of the subscriber parameters; and notifying, from the NFService Consumer to the subscribed external entity, of the event changesfor the one or combination of the subscriber parameters.

According to a further aspect, the functional entity is a BindingSupport Function (BSF).

According to a further aspect, the NF Service Consumer is a NetworkExposure Function (NEF) or a Network Data Analytics Function (NWDAF).

According to a fifth aspect, the invention provides a 5G system (5GS)configured to allow queries of Policy Control Function (PCF) bindinginformation for an address range, the 5GS comprising a Network Function(NF) Service Consumer, and a functional entity, wherein the functionalentity comprises binding information stored therein and the bindinginformation comprises: Protocol Data Unit (PDU) sessions information anda list comprising one or more subscribers identities (IDs) and/or PCFinstance IDs, wherein: the NF Service Consumer is configured to querythe functional entity, based on one or a combination of queryparameters, for all binding information matching the query parameters;and the functional entity is configured to notify to the NF ServiceConsumer, any binding information that matches the query parameters,wherein the query parameters comprise: a MAC or IP address range, a DataNetwork Name (DNN), Subscription Permanent Identifier (SUPI), GenericPublic Subscription Identifier (GPSI), a Single Network Slice SelectionIdentifier (S-NSSAI), and/or IP domain

According to a further aspect, the 5GS further comprises a Unified datamanagement (UDM), a Session Management Function (SMF), and a PolicyControl Function (PCF), wherein: the NF Service Consumer is configuredto receive the binding information, match the query parameters,comprising the list of subscriber IDs; the NF Service Consumer isconfigured to query to the UDM, for SMF registration data based on thelist of subscriber IDs, the UDM is configured to reply to the NF ServiceConsumer, to the above query, with SMF registration data matching thelist of subscriber IDs, wherein the SMF registration data comprises oneor more PDU session IDs and/or SMF instance IDs; the NF Service Consumeris configured to receive the SMF registration data; and the NF ServiceConsumer is configured to interact with the SMF and/or the PCF, by usingthe one or more PDU session IDs and/or SMF instance IDs.

According to a sixth aspect, the invention provides a communicationsystem, wherein the system comprises an external entity and a 5G system(5GS), comprising a Network Function (NF) Service Consumer, wherein: theexternal entity is configured to query the NF Service Consumer, forinformation matching one or more of a combination of query parameters,wherein the query parameters comprise: a MAC or IP address range, a DataNetwork Name (DNN), a Subscription Permanent Identifier (SUPI), aGeneric Public Subscription Identifier (GPSI), a Single Network SliceSelection Identifier (S-NSSAI), and/or IP domain; the 5GS and the NFService Consumer are configured as defined in the fifth aspect or theprevious aspect; and the NF Service Consumer is configured to notify tothe external entity, of the information matching the query parameters.

According to a seventh aspect, the invention provides a 5G system (5GS),configured to allow subscription to Policy Control Function (PCF)binding events for an address range, wherein the 5GS comprises a NetworkFunction (NF) Service Consumer, a functional entity, wherein thefunctional entity comprises binding information stored therein and thebinding information comprises: Protocol Data Unit (PDU) sessionsinformation and a list comprising one or more subscribers identities(IDs) and/or PCF instance IDs, wherein: the NF Service Consumer isconfigured to subscribe to the functional entity, to binding informationchanges for one or a combination of subscriber parameters, wherein thesubscriber parameters comprise: a MAC or IP address range, a DataNetwork Name (DNN), a Subscription Permanent Identifier (SUPI), aGeneric Public Subscription Identifier (GPSI), a Single Network SliceSelection Identifier (S-NSSAI), and/or IP domain; the functional entityis configured to send to the NF Service Consumer, a confirmation of thesubscription; the functional entity is configured to detect a change ofthe stored binding information matching one or a combination of thesubscriber parameters for one or more of the subscriber IDs; thefunctional entity is configured to notify of the change of the storedbinding information to the subscribed NF Service Consumer, by sendingnew PDU session binding information associated with the one or moresubscriber IDs; and the NF Service Consumer is configured to receive thenew PDU session binding information associated with the one or moresubscriber IDs.

According to a further aspect, the 5GS further comprises a Unified datamanagement (UDM), a Session Management Function (SMF), and a PolicyControl Function (PCF), wherein: the NF Service Consumer is configuredto query to the UDM for SMF registration data based on the one or moresubscriber IDs associated with the new PDU session binding information;the UDM is configured to reply to the NF Service Consumer, to the abovequery, with SMF registration data matching the one or more subscriberIDs, wherein the SMF registration data comprises one or more PDU sessionIDs and/or SMF instance IDs; the NF Service Consumer is configured toupdate the SMF registration data; and the NF Service Consumer isconfigured to interact with the SMF and/or the PCF, using the one ormore PDU session IDs and/or SMF instance IDs.

According to an eighth aspect, the invention provides a communicationsystem, wherein the system comprises an external entity and a 5G system(5GS), comprising a Network Function (NF) Service Consumer, wherein: theexternal entity is configured to subscribe to the NF Service Consumer,to event changes for information matching one or a combination ofsubscriber parameters, wherein the query parameters comprise: a MAC orIP address range, a Data Network Name (DNN), a Subscription PermanentIdentifier (SUPI), a Generic Public Subscription Identifier (GPSI), aSingle Network Slice Selection Identifier (S-NSSAI), and/or IP domain;the 5GS and the NF Service Consumer are configured as defined in theseventh or previous aspect; the 5GS is configured to notify to the NFService Consumer, of any event changes for the one or combination of thesubscriber parameters; and the NF Service Consumer is configured tonotify to the subscribed external entity, of the event changes for theone or combination of the subscriber parameters.

According to a further aspect, the 5GS of any of the previous aspectsand the communication system any of the previous aspects, the functionalentity is a Binding Support Function (BSF).

According to a further aspect, the 5GS of any of the previous aspectsand the communication system any of the previous aspects, the NF ServiceConsumer is a Network Exposure Function (NEF) or a Network DataAnalytics Function (NWDAF).

Other aspects, features, and advantages will be apparent from thesummary above, as well as from the description that follows, includingthe figures and the claims.

According to a further embodiment, the invention provides a method forquerying Policy Control Function (PCF) bindings information for anaddress range in a 5G system (thus, enabling the use of secondaryauthentication and/or analytics). This method is illustrated in FIG. 6and describes the interaction between the NF Service Consumer and afunctional entity such as, for example, a BSF, to obtain a UE ID and PCFinstance ID, upon a query based on: an address range (IP or MAC), DNN,SUPI, GPSI, S-NSSAI, and/or IP domain.

In FIG. 6 , given an address range, DNN, SUPI, GPSI, S-NSSAI, or IPdomain of interest where the subscriber identities or PDU Session IDsare not known, a NF Service Consumer (e.g. NEF, NWDAF) queries, in stepS21, the functional entity for all known binding information matchingone or a combination of the following query parameters: address range(IP, MAC), DNN, SUPI, GPSI, S-NSSAI, and IP domain.

In step S22, the functional entity replies to the NF Service Consumerwith the binding information known to it matching the query parameters.The binding information may comprise, for example, a list comprising oneor more subscriber identities, IDs, and/or a PCF instance ID.

Also, according to a further embodiment, in order that a given consumercan be notified whenever there is a binding change (e.g. when a PDUsession is added/removed), the invention provides a method forsubscribing into PCF Binding events for a given address range (IP, MAC),DNN, SUPI, GPSI, S-NSSAI, and/or IP domain. This method is illustratedin FIG. 7 and comprises the following steps.

In FIG. 7 , given an address range, DNN, SUPI, GPSI, S-NSSAI, or IPdomain of interest where the subscriber identities, IDS, or PDU SessionIDs are not known, a NF Service Consumer (e.g. NEF, NWDAF) subscribes,in step S31, on the functional entity to binding changes for one or acombination of the following query parameters: address range (IP, MAC),DNN, SUPI, GPSI, S-NSSAI, and IP domain.

In step S32, the functional entity confirms the subscription, i.e.returns the subscriber status.

In step S331, there is a change in the bindings stored in the functionalentity matching the parameters of step S31, e.g. a new PDU sessionbinding is or was registered or removed by a PCF for the given IP or MACaddress range for one or more subscriber IDs, the functional entitynotifies the subscribed NF Service Consumer, in step S332, with theevent information, namely including the information on the new PDUsession binding or removed PDU session binding.

The application of the above methods give rise to two exemplaryembodiments as shown in FIGS. 8 and 9 , respectively.

In particular, FIG. 8 illustrates a flow for addressing NFs based on asubscriber address range according to an exemplary embodiment of theinvention. FIG. 9 illustrates a flow for notification of changes basedon a subscriber address range according to an embodiment of theinvention.

In FIG. 8 , given an address range, DNN, SUPI, GPSI, S-NSSAI, or IPdomain of interest where the subscriber identities or PDU Session IDsare not known, the NF Service Consumer and functional entity firstperform the same steps as described above for the method of FIG. 6(steps S21 and S22).

In step S23, the NF Service Consumer has received a list of subscriberIDs. Now, the NF Service Consumer has a list of current subscribersmatching the address range.

In step S24, the NF Service Consumer queries to the UDM for SMFregistration data, wherein the SMF registration data comprise a PDUsession ID and a SMF instance ID for the given subscriber IDs.

In step S25, the UDM replies to the above query with data including PDUsession ID and SMF instance ID.

In step S26, the NF Service Consumer receives the data of step S25.Thus, the NF Service Consumer has a list linking theresponsible/associated SMFs and/or PCFs for a given address range.

In step S27, the NF Service Consumer can now interact with NFs (e.g.with the SMF and/or PCF) responsible for the mapped PDU sessions. Forexample, the NF Service Consumer may request and/or subscribe to eventsfor a given PDU session.

In FIG. 9 , given an address range, DNN, SUPI, GPSI, S-NSSAI, or IPdomain of interest where the subscriber identities (IDs) or PDU SessionIDs are not known, the NF Service Consumer and functional entity firstperform the same steps as described above for the method of FIG. 7(steps S31, S32, S331 and S332). Thus, the NF Service Consumer receivesinformation of a new PDU session binding associated with one or moresubscriber IDs or of the removal of a PDU session binding associatedwith one or more subscriber IDs.

If the information received is that of removal of a PDU session binding,steps S34, S35, S36 may be skipped.

In step S34, the NF Service Consumer queries to the UDM for the SMFregistration data, e.g. PDU session ID and SMF instance ID for the givensubscriber IDs.

In step S35, the UDM replies to the above query with data including PDUsession ID and SMF instance ID for the given subscriber IDs.

In step S36, the NF Service Consumer has received the data of step S35.Thus, the NF Service Consumer knows the responsible SMF and PCF for agiven address range. In the case of a new PDU session the list mayinclude entries included in step S35 while in the case of removed PDUsessions, entries may be removed from the list. The new subscriber ID orIDs and PDU session/s information is now known to the NF ServiceConsumer.

In step S37, the NF Service Consumer can now interact with NFs (e.g.with the SMF and/or PCF) responsible for the mapped PDU sessions. Forexample, the NF Service Consumer may request and/or subscribe to eventsfor a given PDU session or unsubscribe to notifications in the case noPDU session in that NF is required to be tracked.

The application of the above described methods, enables a functionalentity exposing such capability, such as for example a NEF, to apply amethod for application of information retrieval and a method forapplication of event notification, as shown in FIGS. 10 and 11 ,respectively, according to two exemplary embodiments.

In FIG. 10 and FIG. 11 , a communication system comprises an externalentity (such as a third party), a functional entity for applying themethod of FIG. 8 or FIG. 9 , respectively, and a 5G System.

In FIG. 10 , at step S41, the external entity requests information for agiven address range (IP, MAC), DNN, SUPI, GPSI, S-NSSAI, and IP domainwithout having knowledge of 5GS subscriber identifiers.

In step S42, the functional entity applies the method of FIG. 8 forrequesting and retrieving the necessary information from the 5GS.

In step S43, the external entity receives the requested information.

In FIG. 11 , at step S51, the external entity subscribes to events for agiven IP address range, DNN, SUPI, GPSI, S-NSSAI, and/or IP domain, sothat the external entity can receive events regarding changes for agiven address range, DNN, SUPI, GPSI, S-NSSAI, and/or IP domain withouthaving knowledge of 5GS subscriber identifiers.

In step S52, the functional entity applies the described method of FIG.9 for subscribing to the necessary information from the 5GS.

In step S53, the 5GS notifies of events to the functional entity.

In step S54, the functional entity generates an event notificationtowards the external entity.

While embodiments of the invention have been illustrated and describedin detail in the drawings and foregoing description, such illustrationand description are to be considered illustrative or exemplary and notrestrictive. It will be understood that changes and modifications may bemade by those of ordinary skill within the scope of the followingclaims. In particular, the present invention covers further embodimentswith any combination of features from different embodiments describedabove and below. Additionally, statements made herein characterizing theinvention refer to an embodiment of the invention and not necessarilyall embodiments.

The terms used in the claims should be construed to have the broadestreasonable interpretation consistent with the foregoing description. Forexample, the use of the article “a” or “the” in introducing an elementshould not be interpreted as being exclusive of a plurality of elements.Likewise, the recitation of “or” should be interpreted as beinginclusive, such that the recitation of “A or B” is not exclusive of “Aand B,” unless it is clear from the context or the foregoing descriptionthat only one of A and B is intended. Further, the recitation of “atleast one of A, B and C” should be interpreted as one or more of a groupof elements consisting of A, B and C, and should not be interpreted asrequiring at least one of each of the listed elements A, B and C,regardless of whether A, B and C are related as categories or otherwise.Moreover, the recitation of “A, B and/or C” or “at least one of A, B orC” should be interpreted as including any singular entity from thelisted elements, e.g., A, any subset from the listed elements, e.g., Aand B, or the entire list of elements A, B and C.

1. A method for subscribing for Policy Control Function (PCF) bindingevents for an address range in a 5G system (5GS), wherein the 5GScomprises a Network Function (NF) Service Consumer and a functionalentity, wherein the functional entity comprises binding informationstored therein and the binding information comprises: Protocol Data Unit(PDU) sessions information and a list comprising one or more subscribersidentities (IDs) and/or PCF instance IDs, the method comprising:subscribing, from the NF Service Consumer to the functional entity, tobinding information changes for one or a combination of subscriberparameters, wherein the subscriber parameters comprise: a MAC or IPaddress range, a Data Network Name (DNN), a Subscription PermanentIdentifier (SUPI), a Generic Public Subscription Identifier (GPSI), aSingle Network Slice Selection Identifier (S-NSSAI), and/or an IPdomain; sending, from the functional entity to the NF Service Consumer,a confirmation of the subscription; detecting, by the functional entity,a change of the stored binding information matching one or a combinationof the subscriber parameters for one or more of the subscriber IDs;notifying of the change of the stored binding information, from thefunctional entity to the subscribed NF Service Consumer, by sending newPDU session binding information associated with the one or moresubscriber IDs; and receiving, at the NF Service Consumer, the new PDUsession binding information associated with the one or more subscriberIDs.
 2. The method of claim 1, wherein the 5GS further comprises aUnified data management (UDM), a Session Management Function (SMF), anda PCF, and wherein the method further comprises: querying, from the NFService Consumer to the UDM, for SMF registration data based on the oneor more subscriber IDs associated with the new PDU session bindinginformation; replying, from the UDM to the NF Service Consumer, to thequery, with SMF registration data matching the one or more subscriberIDs, wherein the SMF registration data comprises one or more PDU sessionIDs and/or SMF instance IDs; updating, at the NF Service Consumer, theSMF registration data; and interacting, from the NF Service Consumer tothe SMF and/or the PCF, using the one or more PDU session IDs and/or SMFinstance IDs.
 3. The method of claim 1, further comprising: subscribing,from an external entity to the NF Service Consumer, to event changes forinformation matching one or a combination of subscriber parameters,wherein the query parameters comprise: the MAC or IP address range, theDNN, the SUPI, the GPSI, the S-NSSAI, and/or the IP domain; notifying,from the 5G system to the NF Service Consumer, of any event changes forthe one or combination of the subscriber parameters; and notifying, fromthe NF Service Consumer to the subscribed external entity, of the eventchanges for the one or combination of the subscriber parameters.
 4. Themethod of claim 1, wherein: the functional entity is a Binding SupportFunction (BSF); and/or the NF Service Consumer is a Network ExposureFunction (NEF) or a Network Data Analytics Function (NWDAF).
 5. A 5Gsystem (5GS) for allowing subscription to Policy Control Function (PCF)binding events for an address range, wherein the 5GS comprises: aNetwork Function (NF) Service Consumer; and a functional entity; whereinthe functional entity comprises binding information stored therein andthe binding information comprises: Protocol Data Unit (PDU) sessionsinformation and a list comprising one or more subscribers identities(IDs) and/or PCF instance IDs; wherein the NF Service Consumer isconfigured to subscribe to the functional entity, to binding informationchanges for one or a combination of subscriber parameters, wherein thesubscriber parameters comprise: a Media Access Control (MAC) or IPaddress range, a Data Network Name (DNN), a Subscription PermanentIdentifier (SUPI), a Generic Public Subscription Identifier (GPSI), aSingle Network Slice Selection Identifier (S-NSSAI), and/or an IPdomain; wherein the functional entity is configured to send to the NFService Consumer, a confirmation of the subscription; wherein thefunctional entity is configured to detect a change of the stored bindinginformation matching one or a combination of the subscriber parametersfor one or more of the subscriber IDs; wherein the functional entity isconfigured to notify of the change of the stored binding information tothe subscribed NF Service Consumer, by sending new PDU session bindinginformation associated with the one or more subscriber IDs; and whereinthe NF Service Consumer is configured to receive the new PDU sessionbinding information associated with the one or more subscriber IDs. 6.The 5GS of claim 5, further comprising: a Unified data management (UDM);a Session Management Function (SMF); and a PCF; wherein the NF ServiceConsumer is configured to query to the UDM for SMF registration databased on the one or more subscriber IDs associated with the new PDUsession binding information; wherein the UDM is configured to reply tothe NF Service Consumer, to the query, with SMF registration datamatching the one or more subscriber IDs, wherein the SMF registrationdata comprises one or more PDU session IDs and/or SMF instance IDs;wherein the NF Service Consumer is configured to update the SMFregistration data; and wherein the NF Service Consumer is configured tointeract with the SMF and/or the PCF, using the one or more PDU sessionIDs and/or SMF instance IDs.
 7. The 5GS of claim 5, wherein the 5GS ispart of a communication system, wherein the communication systemcomprises an external entity and the 5GS; wherein the external entity isconfigured to subscribe to the NF Service Consumer, to event changes forinformation matching one or a combination of subscriber parameters,wherein the query parameters comprise: the MAC or IP address range, theDNN, the SUPI, the GPSI, the S-NSSAI, and/or the IP domain; wherein the5GS is configured to notify to the NF Service Consumer of any eventchanges for the one or combination of the subscriber parameters; andwherein the NF Service Consumer is configured to notify to thesubscribed external entity of the event changes for the one orcombination of the subscriber parameters.
 8. The 5GS of claim 5,wherein: the functional entity is a Binding Support Function (BSF);and/or the NF Service Consumer is a Network Exposure Function (NEF) or aNetwork Data Analytics Function (NWDAF).